In order to have a fair test only the height from which the ball was dropped was altered. The mass of the ball was kept constant and the flour was shaken within the container to as near a horizontal level as possible so that it did not affect the next result by causing the depth of the crater to be changed. A fair test is important to acquire precise results. In addition, I checked that the ruler was always vertical and I also made sure the calibrating stick was at the lowest point at each crater.

Measurements:

The heights dropped ranged from 15 cm to 115 cm adding 15cm in height for each time for the next reading. The number of readings taken was 7 because this is an appropriate number of readings to be able to draw a precise graph and a good range of results. Four repeat readings were taken for each height to obtain an accurate average to be used for the graph. As shown in the preliminary work, a large range of heights is required to get a satisfactory range of results. The calibrating stick was marked in cm and mm to obtain accurate results.

Scientific Knowledge:

As the 35.4g ball is raised above the flour, an upward vertical force equal to 0.354N must be applied to the object in order to lift it.

There are many ways in which the investigation could be improved. Individual results could be made more accurate by using a more reliable source other than a hand to drop the ball from the height. The ball could be rolled off a platform at the different heights. The reliability of the data set could be improved by having a bigger range of results and more repeat readings measured using a more accurate calibration material so that results may be more accurate. The ball could be dropped with different force to see how this would change the results, the effect of speed when hitting the flour. However this may be difficult to carry out as it would have to be a fair test and to keep the force applied the same for each reading it would be difficult.

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